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RE: New battery with old converter?
Do you have proof it will take 3 times longer to charge 3 batteries?
The 3 batteries have 1/3 the internal resistance. That's a major factor in charging. It may not take much longer to charge 3 vs. 1 battery.
Sal
The charge rate is 45a. It will take 3 times longer to charge the 3 compared to 1. Dunno if that's going to be an issue.
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Salvo
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05/25/12 12:15pm |
Tech Issues
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RE: Electrical shock off of propane valve handle please help!!!
Trying to get an understanding of what's going on. With an open ground at the shore ac connection, the RV chassis has a floating ground. Due to emi capacitors within the converter (one cap goes from hot to ground the other cap goes from neutral to ground), the caps create a voltage divider. You should see 60V ac when measuring from chassis to earth ground. Since the emi caps do not have large capacitance values, there isn't much power behind the 60V. Worst case, the OP should only get a slight tingle when touching the propane tank.
Sal
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Salvo
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05/24/12 01:17pm |
Tech Issues
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RE: AC/DC Frame Grounding. Need help.
You got me mixed up. I would never advocate bonding. If you bond, you're one fault away from electrocution. If you do not bond, you're two faults away from electrocution. I like my odds when not bonding. I did not bond my generator that's mounted in my MH.
What happens if you drop a hair dryer into a bathtub you're in? If the ac is bonded, it could be lights out. If not bonded, other than a wet dryer, nothing happens!
There is no requirement to bond your generator. If there is such a requirement, the manufacturer would have done so.
Sal
why does larry's article cover bonding a floating ground invertor such as mine?
http://blog.rv.net/2009/10/generator-bonding-and-grounding/
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Salvo
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05/23/12 11:06pm |
Tech Issues
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RE: AC/DC Frame Grounding. Need help.
If neutral is bonded and ground connected to frame then there is a shock hazard. Bonding (connecting neutral to ac ground) is controversial. You now introduce an added shock hazard. Very few portable generators have a bonded neutral. There is no bonding requirement for your generator.
I would keep away from it. That said, if you want GFCI then you must bond the gen.
SaL
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Salvo
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05/23/12 09:42pm |
Tech Issues
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RE: AC/DC Frame Grounding. Need help.
That buss is not called "negative", but ac ground. The green wire from the converter is connected to that buss bar. This buss should have a connection to chassis/frame.
Sal
People keep saying I need to ground that negative to the frame. Am I hearing correctly?
thanks
Matt
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Salvo
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05/23/12 07:37pm |
Tech Issues
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RE: AC/DC Frame Grounding. Need help.
You will need to connect the ac ground bus to chassis. This is a single point connection. I would double check with an ohm meter to verify that this connection is not yet in place. There should be zero ohms between chassis and ground of an ac receptacle.
Sal
So, when I install the breaker box, I will be running a wire from the negative ground bus in the breaker box to the frame, thus grounding the 120 ac to the frame.
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Salvo
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05/23/12 07:02pm |
Tech Issues
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RE: AC/DC Frame Grounding. Need help.
You shouldn't have to make any wiring mods to the ac or dc circuits. AC ground should already be connected to trailer frame.
BTW, when using the gen, ac ground is floating. It has no electrical reference.
Sal
Thanks guys. I plan on grounding the ac from the negative bus bar in the breaker box to the trailer frame. As stated, the neutral will remain floating.
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Salvo
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05/23/12 06:39pm |
Tech Issues
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RE: Starting the Solar Power System
It's impossible to fuse one or two strings. The fuse will never blow. Arrays with 3 or more parallel strings can and should be fused.
PV cells are current sources, not voltage sources (like a battery). Shorting a voltage source is a big deal. Shorting a current source is no big thing. The shorting current is behaved and predictable.
Sal
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Salvo
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05/23/12 06:23pm |
Tech Issues
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RE: MFGR Battery charging specs
Interesting that they don't specify a max charge current. Given the low battery resistance, a fairly large current can be generated at 14.6V.
Throwing out some numbers:
Battery resistance = 5 m ohm
cable resistance = 5 m ohm
Battery voltage = 12.5V
max charging current = 14.6V - 12.5V / 10 m ohm = 210 A
It's questionable the battery can handle that much current. You may want to ask for a current spec.
Sal
Right there, on the top of the batteries are the charging specs!
Bulk/Absorption/Equalize: 13.8 - 14.6.
Float: 13.4 - 13.6.
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Salvo
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05/22/12 12:13pm |
Tech Issues
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RE: does solar play well with a converter?
The key to this question is measuring battery voltage. If you want to get more exact, you'll need to measure converter and CC cable resistance as well as battery (internal) resistance.
Sal
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Salvo
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05/21/12 11:26am |
Tech Issues
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RE: Parallel or Series Solar?
Hey, just don't read the post! It's that simple. I avoid you constant questioning of Voc. I've answered the issue once. That would be enough!
Sal
This is the classic reason why parallel is better. The bypass diodes do not help.The series vs parallel debate is not as clear cut as some think. I think we've been around the block on this enough.. for me.
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Salvo
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05/20/12 01:26pm |
Tech Issues
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RE: MPPT Controller Max OCV Cloud Fringing Tolerance
**** happens. I would go with lower voltage. I doubt there's a warning sign stating LETHAL HIGH VOLTAGE.
Also, the system will be more efficient at lower voltage.
Sal
The wire is insulated right?
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Salvo
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05/20/12 12:59pm |
Tech Issues
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RE: Parallel or Series Solar?
Thanks for running this test. This scenario is more prevalent than you think. Trees can easily shade one panel and leave the other in the sun. In summer, I'm usually partially in shade to keep the RV cooler. It's always a trade off between maximizing solar charging and minimizing solar load to the rest of the RV.
Reading your graph, I get:
Series or parallel in full sun is about 28A, or 14A per panel.
Series with one panel shaded: 4A
Parallel with one panel shaded: 15A
This is the classic reason why parallel is better. A series array will limit current to that of the least producing panel. The bypass diodes do not help.
The series vs parallel debate is not as clear cut as some think.
Sal
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Salvo
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05/20/12 12:29pm |
Tech Issues
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RE: Parallel or Series Solar?
Sounds like you prefer mppt only because the pwm controller goes into float after 4 hours. If batteries remain below float voltage throughout the charge, you could connect array directly to batteries. That measurement should provide pwm performance without going into float mode after 4 hrs.
Sal
I tested my system using each controller
I found I prefer the MPPT controller
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Salvo
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05/19/12 08:06pm |
Tech Issues
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RE: Parallel or Series Solar?
Good for you! Work is good. When you get some spare time can you run the shade test I suggested. Angle one panel 45 degrees off of sun to simulate one panel in the shade.
Sal
Hi Sal
Sorry but I have been busy earning a living.
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Salvo
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05/19/12 07:49pm |
Tech Issues
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RE: PowerMax PM3B-100 (100 Amp 3-Stage Converter/Charger)
It's a good feature if the PD can back it up by putting out rated current. It never does that. The Iota is excellent for dry camping. It will supply rated current.
Sal
A nice feature to have when dry camping.
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Salvo
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05/18/12 11:37am |
Tech Issues
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RE: Parallel or Series Solar?
You'll need 12V panels when using a pwm controller. I haven't seen any 12V panels that are greater than 135W.
Don't let the test in this thread misguide you. As long as you use 12V panels, there's not much performance difference between pwm and mppt controllers.
BTW, what happened to the OP? Thought we're getting more shading testing.
Sal
I plan to use just two panels, of a size between 130 and 200 watts each. And I will have two 6V GC batteries. I had planned to use a Morningstar Tristar 45 PVM controller, and wire in parallel, and in fact, just received the Tristar. But this discussion has me wondering if I should have paid the extra and gone MPPT.
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Salvo
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05/17/12 07:59pm |
Tech Issues
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RE: "Ole School" Amp Meter on Solar Panel
If you got several panels in parallel, panel current will only tell you the maximum power point current. The actual charging current will be over two times greater. In that respect this current is not very useful.
You can get the Turnigy Watt meter. This meter will tell you how much power the panels are producing. This is way more useful info.
Sal
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Salvo
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05/08/12 09:30pm |
Tech Issues
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RE: Solar on a budget
Getting 10.5A is excellent. You don't need mppt. It'll be good to get off the generator!
Sal
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Salvo
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05/02/12 05:34pm |
Tech Issues
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RE: Parallel or Series Solar?
The shading test that the OP made is probably the worst case scenario for parallel and best case for serial. This test makes serial shine!
The OP should run additional tests that are more representative of natural shading conditions. I suggest testing one panel in full sun and the other in shade (not just one cell). You can simulate a shaded panel by angling the panel 45 degrees (or more) away from the sun. The parallel configuration should now outperform serial.
A little example. We got 2 panels, one in shade the other in sun. The shaded panel produces 50% less current. Parallel should produce ~50% more power.
Regarding bypass diodes:
They matter in all configurations as they eliminate hotspots within the panel. But in a parallel configuration, they don't aid in getting more power out of the panel when shade is present.
Here's the deal. In a series string, current is limited to the least productive cell. In parallel, voltage is king. For each panel to be productive, panel voltages need to match. If you got a bypass diode conducting in one of the parallel panels, its output voltage is drastically reduced. The sunny, higher voltage panel is the only one producing power for battery charging.
Interesting... But... I'm here with MrWizard - full shading of a cell doesn't happen in real-life conditions, real shading is almost always translucent.
Salvo - pardon my ignorance, I'm too old to learn again what I've forgotten - and in case of parallel the number of bypass diodes doesn't matter?
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Salvo
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04/30/12 09:46am |
Tech Issues
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